/**
 * Copyright (c) 2021 OceanBase
 * OceanBase CE is licensed under Mulan PubL v2.
 * You can use this software according to the terms and conditions of the Mulan PubL v2.
 * You may obtain a copy of Mulan PubL v2 at:
 *          http://license.coscl.org.cn/MulanPubL-2.0
 * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
 * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
 * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
 * See the Mulan PubL v2 for more details.
 */

#ifndef SRC_SQL_ENGINE_EXPR_OB_EXPR_CONCAT_WS_H_
#define SRC_SQL_ENGINE_EXPR_OB_EXPR_CONCAT_WS_H_
#include "sql/engine/expr/ob_expr_operator.h"
namespace oceanbase {
namespace sql {
// stands for Concatenate With Separator and is a special form of CONCAT()
class ObExprConcatWs : public ObStringExprOperator {
public:
  ObExprConcatWs();
  explicit ObExprConcatWs(common::ObIAllocator& alloc);
  virtual ~ObExprConcatWs();
  virtual int calc_result_typeN(
      ObExprResType& type, ObExprResType* types, int64_t param_num, common::ObExprTypeCtx& type_ctx) const override;
  virtual int calc_resultN(
      common::ObObj& result, const common::ObObj* objs, int64_t param_num, common::ObExprCtx& expr_ctx) const override;
  // connect two strings by separator
  static int concat_ws(
      const common::ObString obj1, const common::ObString obj2, const int64_t buf_len, char** string_buf, int64_t& pos);
  // connect any strings by separator
  static int calc(common::ObObj& result, const common::ObString& sep_str, const common::ObObj* objs,
      const int64_t param_num, common::ObExprCtx& expr_ctx);
  virtual int cg_expr(ObExprCGCtx& expr_cg_ctx, const ObRawExpr& raw_expr, ObExpr& rt_expr) const override;
  static int calc_concat_ws_expr(const ObExpr& expr, ObEvalCtx& ctx, ObDatum& res);
  static int calc(const common::ObString& sep_str, const common::ObIArray<common::ObString>& words,
      common::ObIAllocator& alloc, common::ObString& res_str);

private:
  // disallow copy
  DISALLOW_COPY_AND_ASSIGN(ObExprConcatWs);
};

}  // namespace sql
}  // namespace oceanbase

#endif /* SRC_SQL_ENGINE_EXPR_OB_EXPR_CONCAT_WS_H_ */
